Drivers who usually cross the Memorial Bridge overlooking Cargill Falls can expect some detours next year as the state prepares to refurbish the 87-year-old span.

The state Department of Transportation plans to rehabilitate the superstructure and other portions of the bridge beginning next spring, said Jon Hagert, the department’s project manager for bridge design.

Hagert said plans call for replacing the bridge’s sidewalks, light parapets, arch and barriers while also resurfacing the road.

“This work will be done with historic sensitivity,” Hagert said.

Preliminary project costs are estimated at $2.5 million using state and federal funding. Construction is tentatively scheduled to begin April 2014 and likely be completed in November 2014.

“This could have been a two-season project if traffic on the bridge was maintained,” Hagert said.

Cars will likely be detoured up Kennedy Drive, over Bridge Street and onto Church Street. Trucks will shift their routes to Route 171 and over Church Street, said Town Administrator Doug Cutler.

Since the Memorial Bridge is one of the main routes for ambulances traveling to nearby Day Kimball Hospital, officials were invited to a recent public hearing on the project to keep them informed of expected traffic pattern changes.

Charlene Leith-Bushey, hospital spokeswoman, said the work could add a “couple of minutes” extra to an ambulance’s arrival time to the hospital.

Police Chief Rick Hayes said he’s spoken with local EMS departments about the planned traffic detours.

The bridge and its deteriorating condition have long been the focus of possible rehabilitation. The deck’s sidewalks, covered in steel plates, are crumbing, with fist-sized chunks of stone scattered on the curb. One of the bridge’s four parapet lights is missing, and the span’s arch is pitted and pockmarked.

However, there are no safety issues with the bridge, officials said.

Hagert said the use of pre-fabricated sections, including ornate portions, will enable crews to finish the job faster. No scaffolding is planned for the project.

Cutler said the project will require the relocation of sewer and water lines, although the price of those changes, which the town will be reimbursed for, has not yet been determined, Cutler said.